`docspec-http`

Library providing an Axum-based HTTP server that wraps a DocSpec conversion pipeline. Designed for embedding in custom binaries or running via the unified docspec http subcommand.

Send markdown (Content-Type: text/markdown), HTML (Content-Type: text/html), or DOCX (Content-Type: application/vnd.openxmlformats-officedocument.wordprocessingml.document), receive BlockNote JSON (default), HTML (Accept: text/html), oxa.dev JSON (Accept: application/vnd.oxa+json), or Pandoc native (Accept: application/vnd.pandoc.native). The underlying DocSpec pipeline is streaming, but this v1 HTTP wrapper buffers the request body and the conversion output in memory before responding. End-to-end streaming over HTTP is planned for a future version. For now, request size scales with available memory.

HTML is paragraph-only. The HTML reader currently parses <p> elements only, and the HTML writer currently emits only paragraph events. Other HTML input elements and non-paragraph output events (headings, lists, tables, formatting, etc.) are silently dropped. See docspec-html-reader and docspec-html-writer.

When to Use This Crate

Use docspec-http directly when you're embedding the HTTP server into your own binary or need programmatic control over server startup, configuration, or telemetry initialization.

For end users who want a running HTTP server without writing Rust code, install docspec-cli and run docspec http.

Quick Start

[dependencies]
docspec-http = "1.5"
tokio = { version = "1", features = ["full"] }

use docspec_http::{serve, server::ServerConfig};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let config = ServerConfig { host: "127.0.0.1".to_string(), port: 3000 };
    serve(config).await?;
    Ok(())
}

Once the server is running, send documents with curl:

# Convert Markdown to BlockNote JSON
curl -X POST \
     -H 'Content-Type: text/markdown' \
     -d '# Hello' \
     http://localhost:3000/conversion

# Convert HTML to BlockNote JSON
curl -X POST \
     -H 'Content-Type: text/html' \
     -d '<p>Hello</p>' \
     http://localhost:3000/conversion

# Convert DOCX to BlockNote JSON
curl -X POST \
     -H 'Content-Type: application/vnd.openxmlformats-officedocument.wordprocessingml.document' \
     --data-binary @document.docx \
     http://localhost:3000/conversion

Public API

Item	Kind	Description
`serve(config: ServerConfig)`	async fn	Start the HTTP server with the given configuration. Runs until SIGINT or SIGTERM.
`ServerConfig`	struct	Server bind configuration: `host: String`, `port: u16`.
`cli::Args`	struct	Clap-derived argument struct for `--host` and `--port`. Useful when building a CLI that delegates to this library.
`init_telemetry(dsn: Option<&str>)`	fn	Initialize Sentry integration. Call before `serve()` if you want error reporting.
`init_tracing()`	fn	Initialize the tracing subscriber (stderr, INFO, pretty format). Call before `serve()`.
`TelemetryGuard`	struct	Drop guard returned by `init_telemetry()`. Keep alive for the duration of the process to ensure Sentry flushes on exit.

Endpoints

Method	Path	Description
POST	/conversion	Convert markdown, HTML, or DOCX to BlockNote (default), HTML, oxa.dev JSON, or Pandoc native
OPTIONS	/conversion	Preflight / allowed methods
GET	/health	Liveness check
HEAD	/health	Liveness check (no body)
OPTIONS	/health	Allowed methods
GET	/metrics	Prometheus metrics in exposition format 0.0.4

Request / Response Headers

X-Request-ID: Generated (UUID v4) if the request omits it. Echoed back unchanged if present.

X-Trace-ID: Echoed back if present. Never generated by the server.

Cache-Control: max-age=0, private, must-revalidate on every response, including errors.

Error Responses

All errors use RFC 7807 Problem Details JSON (application/problem+json; charset=utf-8).

Code	Meaning
400	Empty body or invalid UTF-8
404	Unknown path
405	Wrong method (response includes `Allow` header)
406	`Accept` header excludes all supported output types
415	`Content-Type` must be `text/markdown`, `text/html`, or `application/vnd.openxmlformats-officedocument.wordprocessingml.document`
422	Input parse error (malformed markdown, HTML, or DOCX)
500	Internal conversion error

Accepted Accept values for /conversion: text/html (HTML), application/vnd.oxa+json (oxa.dev), application/vnd.pandoc.native (Pandoc native), application/vnd.docspec.blocknote+json, application/vnd.blocknote+json (BlockNote alias), application/*, or */*. Wildcards and missing Accept default to BlockNote for back-compat. Anything else returns 406.

Deployment Notes

TLS: Use a reverse proxy (nginx, Caddy). The server speaks plain HTTP.

CORS: Use a reverse proxy. No CORS headers are added.

Auth: Use a reverse proxy or upstream gateway.

Body size: No limit. Large documents are accepted. DoS risk is accepted. Both the request body and the conversion output are held in memory for the duration of the request.

Request timeout: No timeout. Slow clients can hang a connection indefinitely.

Logging

Logs go to stderr at INFO level in pretty format. There are no flags to change the log level or format.

Observability

docspec-http integrates with Sentry for error reporting. Activation is fully opt-in via environment variables — the binary has zero Sentry overhead when no DSN is configured.

Activation

Set ONE of the following to enable Sentry:

DOCSPEC_SENTRY_DSN — docspec-specific override (preferred)
SENTRY_DSN — Sentry's standard convention (fallback)

If both are set, DOCSPEC_SENTRY_DSN wins. An empty string or malformed DSN is treated as "not set" — the server starts normally and logs a warning to stderr.

Configuration (all optional)

These follow Sentry's standard conventions:

SENTRY_ENVIRONMENT — environment name (default: production)
SENTRY_RELEASE — release identifier (default: auto, docspec-http@<version>)
SENTRY_SAMPLE_RATE — error sample rate [0.0, 1.0] (default: 1.0)
SENTRY_TRACES_SAMPLE_RATE — performance trace sample rate [0.0, 1.0] (default: 0.0, traces disabled)

What is captured

Signal	Captured?
`500 Internal Server Error` (`HttpError::Internal`)	yes (event)
`422 Unprocessable Entity` (`HttpError::Unprocessable`)	yes (event)
Other 4xx responses	no
Panics	yes (event)
`tracing::error!` calls	yes (event)
`tracing::warn!` calls	yes (breadcrumb)
`tracing::info!`/`debug!` calls	yes (breadcrumb)
Performance transactions	only if `SENTRY_TRACES_SAMPLE_RATE > 0`

Privacy

docspec-http does NOT send the following to Sentry:

Request bodies (markdown, HTML, or DOCX documents)
Response bodies (BlockNote JSON, HTML, oxa.dev JSON, or Pandoc native)
PII (Sentry default: send_default_pii = false)
DSN values (never logged or echoed)

Sentry's default header redaction (Authorization, Cookie, etc.) is preserved.

Each captured event is tagged with request_id (UUID v4) and trace_id (X-Trace-ID header value, if present) for correlation with logs.

Wire Contract

Mirrors github.com/docspecio/api v3.0.2 where feasible: same endpoint path, RFC 7807 errors, X-Request-ID/X-Trace-ID header handling. Diverges in supported conversions.

Graceful Shutdown

The server handles SIGINT and SIGTERM. In-flight requests complete before the process exits.

Metrics

docspec-http exposes a Prometheus metrics endpoint on the same port as the main API.

Endpoint: GET /metrics

Format: Prometheus exposition format 0.0.4 (text/plain; version=0.0.4; charset=utf-8)

Auth: None. The endpoint is internal-only. See Security below.

Metric Catalog

Name	Type	Labels	Description	Buckets
`docspec_http_requests_total`	counter	`method`, `path`, `status`	Total HTTP requests received	—
`docspec_http_request_duration_seconds`	histogram	`method`, `path`, `status`	HTTP request latency in seconds	0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, 10.0
`docspec_http_request_body_bytes`	histogram	`input_mime_type`	HTTP request body size in bytes, labeled by input MIME type	100, 200, 400, 800, 1600, 3200, 6400, 12800, 25600, 51200, 102400, 204800
`docspec_conversions_total`	counter	`result`, `error_class`, `input_mime_type`, `output_mime_type`	Total document conversions, labeled by result, error class, and input/output MIME type	—
`docspec_conversion_duration_seconds`	histogram	`result`, `input_mime_type`, `output_mime_type`	Document conversion duration in seconds, labeled by result and input/output MIME type	0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, 10.0
`docspec_conversion_output_bytes` (NEW)	histogram	`input_mime_type`, `output_mime_type`	Document conversion output size in bytes (success only)	100, 200, 400, 800, 1600, 3200, 6400, 12800, 25600, 51200, 102400, 204800

Label Values

result: success, client_error, server_error

error_class: body_not_utf8, empty_body, internal, method_not_allowed, not_acceptable, not_found, unprocessable, unsupported_media_type, none (only when result=success)

input_mime_type: text/markdown (the request's Content-Type matched the markdown reader), text/html (the request's Content-Type matched the HTML reader), application/vnd.openxmlformats-officedocument.wordprocessingml.document (the request's Content-Type matched the DOCX reader), unsupported (Content-Type header present but not a supported input format), none (Content-Type header absent).

output_mime_type: application/vnd.docspec.blocknote+json (conversion succeeded; output produced by the BlockNote writer), text/html (conversion succeeded; output produced by the HTML writer), application/vnd.oxa+json (conversion succeeded; output produced by the oxa.dev writer), application/vnd.pandoc.native (conversion succeeded; output produced by the Pandoc native writer), none (no output produced — any error path).

path: matched route template (/conversion, /health) or unknown for fallback handlers

status: numeric HTTP status code as a string (e.g., "200", "422")

method: HTTP method as a string (e.g., "GET", "POST")

Cardinality Guarantees

path is bounded to {"/conversion", "/health", "unknown"}. error_class is bounded to 9 values. result is bounded to 3 values. Per-request identifiers (X-Request-ID, X-Trace-ID) are never used as labels. input_mime_type is bounded to 5 values (text/markdown, text/html, application/vnd.openxmlformats-officedocument.wordprocessingml.document, unsupported, none). output_mime_type is bounded to 5 values (application/vnd.docspec.blocknote+json, text/html, application/vnd.oxa+json, application/vnd.pandoc.native, none). Both come from a fixed set of &'static str constants in the source — never from raw header values.

Scrape Model

Each pod maintains its own in-memory metrics. Prometheus scrapes each pod independently. No inter-pod communication is required. Aggregate across pods using PromQL.

Upkeep runs every 5 seconds, keeping histogram internal state bounded.

The /metrics route is mounted outside the API middleware stack, so it does not include the global Cache-Control header used by API responses.

The body-size histogram (docspec_http_request_body_bytes) only records bodies that passed Content-Type and Accept validation. Rejected requests are not counted.

The output-bytes histogram (docspec_conversion_output_bytes) only records observations for successful conversions. Failed conversions do not produce output, so no observation is recorded.

Example PromQL Queries

Per-pod request rate:

rate(docspec_http_requests_total[5m])

Aggregate p99 latency across all pods:

histogram_quantile(0.99, sum by (le) (rate(docspec_http_request_duration_seconds_bucket[5m])))

Error rate broken down by error class:

rate(docspec_conversions_total{result!="success"}[5m])

Body-size p95:

histogram_quantile(0.95, sum by (le) (rate(docspec_http_request_body_bytes_bucket[5m])))

Body-size p95 by input format:

histogram_quantile(0.95, sum by (le, input_mime_type) (rate(docspec_http_request_body_bytes_bucket[5m])))

Conversion success rate by input format:

sum by (input_mime_type) (rate(docspec_conversions_total{result="success"}[5m]))
  / sum by (input_mime_type) (rate(docspec_conversions_total[5m]))

Security

/metrics has no authentication. It's intended for internal scraping only. Deploy behind a private overlay network or a Kubernetes NetworkPolicy that restricts access to your Prometheus pods.

docspec-http 1.6.0

docspec-http